1. Field of the Invention
The present invention relates to a pseudo I/O system, which is connected to a device to be tested, simulating an actual I/O system, and a method thereof.
2. Description of the Related Art
Conventionally, there is a system comprising an I/O device connected to a SCSI or FC interface. Among others, for example, there is a system conducting various types of tests on an initiator. Its test method falls into 3 types.
FIGS. 1A, 1B, and 1C show the conventional three test methods.
The conventional three test methods include (1) a method conducting various types of tests by connecting to an initiator of an actual I/O device such as a hard disk drive, etc. (see FIG. 1A); (2) a method conducting various types of tests by connecting an analyzer having a test capability between an initiator and an actual I/O device (see FIG. 1B); and (3) a method conducting various types of tests by connecting to an initiator of a pseudo I/O system recited in Japanese Patent Publication No. 6-52072 or 5-73446 (see FIG. 1C).
If various types of tests are conducted on an initiator by connecting an actual I/O device to the initiator shown in FIG. 1A with the above described method (1), all of devices to be connected such as a hard disk drive, a tape drive, etc., for which the tests are to be conducted, must be prepared. Additionally, if attempts are made to conduct a test on devices whose type is the same, for example, hard disk drives whose type is the same but whose sector sizes are different, corresponding hard disk drives having different sector sizes must be prepared. Furthermore, it is extremely difficult to conduct a test on an initiator by making an abnormal operation such as no reply, timeout, etc. of an actual I/O occur, even if attempts are made to conduct such a test. This is because the actual I/O does not perform an abnormal operation, when it has no problem.
When various types of tests are conducted on an initiator by connecting an analyzer between the initiator shown in FIG. 1B and an actual I/O device with the above described method (2), it is troublesome that corresponding actual I/O devices must be prepared if the type of an actual I/O device is changed, or if the sector size of an actual I/O device is changed although the type of the device is the same.
Although various types of tests are conducted by connecting to an initiator a pseudo I/O system, which is shown in FIG. 1C and recited in each of the above described Japanese Patent Publications, with the above described method (3), the Japanese Patent Publications target only a test on an interface such as a SCSI interface, etc. Besides, data that are handled by the pseudo I/O system and a connected test system are test data that are set in a fixed manner, and different from those for actual use. Therefore, a test for actual use cannot be conducted. Furthermore, there are problems such that (1) a system cannot run unless a test capability is added to a device to be tested; (2) if a problem that occurs in actual use depends on an address to which data is written, or contents of data, the problem cannot be reproduced, because an interface for writing test address or data is the same as that for writing an address and data when a test is conducted is the same; and (3) data other than data for actual use must be transmitted to an interface to be tested, since settings of various tests must be transmitted to a pseudo I/O system via the interface to be tested such as a SCSI interface, etc.